Er - there's a huge difference between "cheap colo range with a /18 that's spread with snowshoe bulk mailers" and "comcast business ranges ...
Right, those are the extremes but where do you draw the line? In my case I rented a server with an ISP operating legally. I actually checked for abuse complaints of several companies that rented servers and I found complaints about all of them. As for Comcast being the "gold standard" for filtering the only way they can do this is to violate their network policy. After the p2p throttling they claimed they have a "protocol agnostic" network policy. But you can't do that and also block specific ports. Further, if Comcast does block you they often won't tell people why. The exact quote to me was: "it doesn't matter what our privacy policy says, you are not getting the info." They also told me if I registered for a higher level of service somehow the security issues would disappear and there would no longer be blocking. Plus, last year they moved most of their privacy policies from Comcast.NET (covered by TRUSTe) to Comcast.COM (not covered by TRUSTe). If you want to be the "gold standard" for filtering then you will need to violate the privacy of your customers, keep it secret from them so they don't get pissed off, and then the system will be hijacked by the marketing department and used to increase the bottom line. This is getting off the issue of RIPE and abuse but the point is there are tradeoffs for all these actions and abuse is not the only issue in the world. Thank You